1. Field of the Invention
The present invention relates to a focus detecting apparatus and a driving method therefor.
2. Description of the Related Art
As a conventional focus detection method for a camera, there is known a technique of performing focus detection using a line sensor. Japanese Patent Laid-Open No. 10-104502 discloses a technique of extending a focus detection area using an area sensor. In either of the focus detecting apparatuses using those sensors, the number of detection units corresponds to that of sensors, and a number of distance measurement points are provided to detect that an output potential reaches a predetermined value.
To detect the focus, in these detection units, a through current consumes high power in a standby state until a detection signal is received. Particularly, if, for example, the number of distance measurement points is larger, it is necessary to provide a larger number of detection units, and therefore, power consumption is high when detecting the focus.